Floor insulation in loft conversion

XIX

Hello,

I'm currently having a loft conversion done and thought the floor would need to be insulated, but the builder has said there will be enough insulation to meet building regs in the walls and roof. Any thoughts? I always presumed it would be insulated to help stop noise to the bedroom underneath as much as keeping in the warmth

Thanks

Doozergirl

It's a personal choice, certainly not a requirement. If you want that, then you'd have to request it.

brightontraveller

Common fiberglass “ insulation” is a good thermal insulator, but terrible acoustical insulator.

Design, etc without consideration + remedy for airborne and impact noise is ridiculous... builder, architect etc should have spoken/informed you about it prior to starting ? Personally wouldn’t convert any loft without adding soundproofing it adds a miniscule amount too costs..... rarely does anyone say I wish I didn’t soundproof?

Furts

Sound transmission, maybe the mention of Robust Details, and such like should all have been part of your design concepts and design meeting. If you had no design input, or no professional help on board, then that was a very unwise decision.

However, step in now and consider your ceiling below the loft. This should be dense plasterboard, with a minimum mass - you decide here. You could over board what you have - probably the easiest solution. Being pragmatic, couple this with infilling the ceiling void/loft floor with Rockwool or fibreglass. This will help reduce drumming and sound leakage.

I would have thought your Building Inspector would have commented on noise transmission - where do you stand here with your discussions with them?

Gloomendoom

A friend of mine has an old country house. When doing some renovations, he discovered that the voids between the floors were filled with sea shells. Apparently, method used for noise insulation in the 18th century.

gazzak_2

I've just had a loft conversion done and they put another layer of insulation on top of the existing to fill the joists completely. It's lovely and quiet up there.

You're the boss, not the builder. Get him to lay more.

dunroving

If you force too much insulation between the joists are you not risking the ceiling below?

teneighty

XIX wrote: »

Hello,

I'm currently having a loft conversion done and thought the floor would need to be insulated, but the builder has said there will be enough insulation to meet building regs in the walls and roof. Any thoughts? I always presumed it would be insulated to help stop noise to the bedroom underneath as much as keeping in the warmth

Thanks

Building Regulation E2 deals with sound insulation to internal walls and floors. Generally you should have 100mm of mineral wool in the new floor, this applies to extensions and alterations as well as new builds.

If in doubt ask your Building Control Officer.

beaker141

I put rockwool in my loft conversion floor joists, suspended on chicken wire. I'm sure it was a requirement for fire protection but its 10 years ago so I cant recall it.

I'd also put it in from an insulation point of view, lofts can get quite hot so insulating helps to keep heat in the room below rather than it all ending up quickly in the loft.

I have very little sound transmission from the loft, its a combination of the air gap, insulation, properly sized joists with noggins, plastic dpc strip laid on top of each joist to minimise any creaking, chipboard T&G floor joins on the short edge always supported on a joist, screwed and glued down, then topped with an acoustic underlay from Quickstep before laminate floor on top.

The difference to the floor the builder did in the extension is worlds apart.

Norman_Castle

gazzak wrote: »

I've just had a loft conversion done and they put another layer of insulation on top of the existing to fill the joists completely. It's lovely and quiet up there.

What has been done exactly? Old loft insulation left in place with more loft insulation or acoustic insulation on top?
Details would be appreciated as a flat dweller looking for cheap and successful solutions.

Alter_ego

Gloomendoom wrote: »

he discovered that the voids between the floors were filled with sea shells. Apparently, method used for noise insulation in the 18th century.

I bet you could still hear the sea!